An RCC device and a gripper mechanism combination are conventionally arranged in a stacked array. The RCC device and gripper mechanism are separate units with the gripper mechanism suspended from the RCC device for gripping tools or workpieces to be manipulated.
An RCC device is a passive device for aiding insertion and mating maneuvers in robot machines, docking and assembly equipment. An RCC device establishes motion about a remote center of compliance typically at, near or beyond the functioning end of the operator member. The RCC device includes two structures concatenated or serially interconnected between the operator member and a mounting member. In one type of RCC, disclosed in FIG. 1 of U.S. Pat. No. 4,098,001 , (hereinafter U.S. Pat. No. '001) one structure includes flexure means comprised of a number of discrete elements or radial members aligned with conical radii from a center which is the remote center of compliance of the device. The other structure includes flexure means composed of a number of discrete elements which are parallel to each other and which also have localized motion portions.
In another type of RCC device, as disclosed in FIG. 2 of U.S. Pat. No. 4,155,169, (hereinafter U.S. Pat. No. '169) the two structures each include flexure means which are generally flexible or deformable throughout. In one of the structures the flexure means are radial members arranged along conical radii from a center or focus, and that center typically is not coincident with the remote center of compliance of the device. In the other structure a laterally oriented member also includes flexure means which establish a second center or focus. The remote center of compliance is typically somewhere between the two centers or foci and each of the structures contributes to the rotational and the translational action of this type of RCC device. Thus in the RCC device of FIG. 2 of U.S. Pat. No. 4,155,169 both structures constitute a rotational portion, whereas in the RCC devices of U.S. Pat. No. 4,098,001 (FIG. 1) the radial member portion is identified with the rotational action.
In the RCC of U.S. Pat. No. '001, the location of the remote center is determined by the geometry of a plurality of radially disposed members whose focus is a point in space at which the remote center of compliance is located.
In the RCC device of U.S. Pat. No. '169 the location of the remote center is determined by the geometry and stiffness of the radial members as well as by the mechanical stiffness of a deformable element which supports the radial members.
In the RCC device shown in FIG. 2 of U.S. Pat. No. 4,337,579 at least a portion of the operator means is deformable and provides a first motion center. There is a deformable means for supporting the operator means to permit rotation about a projected second center and providing in conjunction with the operator means a remote center of compliance between the first and second centers at, near or beyond the end of the operator means. All of the above disclosures are incorporated herein by reference.
One shortcoming of present apparatus is that the gripper mechanism added on to the RCC device increases the required distance of the remote center of compliance from the RCC device. This is a problem because it is difficult to effectively project the remote center of compliance a large distance from the RCC device. For example, a typical workable distance is set at a ratio of 1:1 with the diameter of the RCC device. The attachment of a gripper mechanism to the RCC device typically compels an increased distance for the remote center of compliance. The separate gripper mechanism also adds size, bulk, cost, and increases the overall number of parts used.